Comparative analysis between express device and Xen Gel stent by IOP in open angle glaucoma uncontrolled with medical treatment: a unicentre, single-blind, randomized controlled clinical trial

Abstract

BACKGROUND Glaucoma is a leading cause of vision loss worldwide, and intraocular pressure (IOP) is the single proven modifiable risk factor for the development and progression of glaucoma. Therefore, the basis of glaucoma treatment is the reduction of IOP. Topical and oral medications, laser trabeculoplasty, and incisional surgery are used to accomplish this goal either alone or in combination. Because of the rates of complications and failure associated with filtration surgery, new implants that attempt to lower IOP in a safer fashion are constantly being explored. Many of these new surgeries fall under the heading of MIGS, most commonly defined as minimally invasive or microinvasive glaucoma surgery. The XEN Gel Stent, which is a subtype of MIGS, uses the subconjunctival space for aqueous drainage but from a novel, ab interno approach. In contrast with traditional ExPRESS device, the XEN stent is significantly smaller and shunts aqueous to the subconjunctival space without the presence of an extraocular reservoir. There is evidence enough of its efficacy in mil-to-moderate open angle glaucoma but is necessary compare the XEN Gel stent technique with an old more patented implant like ExPRESS. OBJECTIVE The main purpose of this study is to compare the efficacy of XEN Gel stent versus ExPRESS device in the treatment of patients diagnosed with mild-to-moderate open angle glaucoma uncontrolled with medical treatment. DESIGN A randomized, single-blinded, controlled clinical trial that will be perform in the Hospital Universitari Josep Trueta within the Oftalmologic unit from September of 2018 to August of 2021. METHODS: 110 patients with mild-to-moderate open angle glaucoma will be recruited with a consecutive method. This patients will be randomly placed in one of the two treatment groups, either Xen Gel stent or ExPRESS device. T- Student test will be used for statistical analysis of the primary objective. U- Mann Whitney test and chi-square test will analyse the secondary objectives